Grinding machines are used to flatten surfaces of machine parts. Grinding machines can include one or two grinding wheels. Where two grinding wheels are found in a grinding machine, a parts carrier is positioned between opposing planar grinding surfaces of the grinding wheels. Where one grinding wheel is found in the grinding machine, the parts carrier is typically positioned below the planar grinding surface of the grinding wheel.
It is necessary to periodically dress and/or true the grinding surface that contacts parts loaded into a parts carrier of the grinding machine. Dressing a grinding wheel refers to removal of swarf, dull grains and bonding material from the grinding material on the grinding surface. Dressing sharpens the grinding wheel. Truing refers to dressing of a wheel to return the grinding surface to its original shape, or the removal of material from the grinding surface of the wheel so that the resultant grinding surface runs true to some other surface.
U.S. Pat. No. 6,338,672 discloses a dressing wheel system for dressing planar grinding surfaces in a grinding machine. In this dressing wheel system, a plurality of planetary dressing wheels are driven by the same pinion drive that typically drives the parts carrier of the grinding machine. The grinding wheel system disclosed in U.S. Pat. No. 6,338,672 works well, but does require loading and unloading of multiple dressing wheels, which increases the downtime of the grinding machine while the grinding surfaces are being dressed.